The present invention relates to what is known as a “grip harvester”, to be more precise, a timber working head for at least one of trimming, cutting, bark-peeling and preferably also felling, and of the type that is arranged to be suspended with its frame in a crane, which timber working head comprises grippers mounted to pivot for the gripping of a tree, trimming means preferably connected to the grippers, a chain saw for the felling and cutting of a tree and driven feed wheels for feed of the felled tree through the timber working head for trimming and cutting.
Harvesters of this type are previously known and have as a rule their feed wheels so arranged relative to the grippers that they accompany the motion of the grippers to and from the gripping position. It has proved to be the case with this arrangement that the feed wheels when gripping a tree trunk with a small diameter do not make contact with the tree in a correct manner, but instead more or less press the tree trunk against the timber working head. This leads to the feed wheels damaging the tree trunk through the feed wheels sliding against the tree trunk, which gives a poorer quality for the tree, and in addition wear of the edge of the feed wheels takes place, which shortens the lifetime of the feed wheels.